This invention relates generally to apparatus and methods for winding wire on a workpiece, and more particularly to apparatus and a method for forming a toroid coil on a toroidal body.
Wire wound toroid cores are frequently used in various types of electrical equipment. In order to optimize the electromagnetic properties of the core, it is formed as an unbroken toroidal body. However, the shape of the toroidal cores makes them difficult to wind with automatic machinery. Yet, to provide large numbers of such cores at a reasonable cost, use of machines in manufacture is mandated. Heretofore, the machines used for winding the cores have been complex and expensive. Further, the rate of completion of the final product, a wound toroidal core, has been relatively slow.
Some of these machines have a rotatable, C-shaped shuttle for carrying a leading end of wire from a source of wire. The core is positioned in the opening in the shuttle with its central opening lying on the circumferential path of the shuttle. As the shuttle rotates through the central opening of the core, wire is wrapped around the core through its central opening, with one turn of coil being formed every rotation of the shuttle. At the same time, the core is slowly rotated (manually or otherwise) on its axis of rotation so that the turns of coil advance around the circumference of the core, thus producing a toroid coil. Alternatively, the shuttle may move around the circumference of the core while the core remains stationary, to form the toroid coil. An example of such a machine is shown in Albo, U.S. Pat. No. 4,379,527. In another type of toroidal core winding machine, wire is pushed by rollers along a circular path having a large diameter in comparison with the diameter of the core. The path passes through the central opening of the core. After a full loop of wire is formed, it is released so that during the formation of the succeeding loop, the preceding loop is constricted around the core. The core must be simultaneously rotated on its axis so that the loops of wire form a toroid coil extending around the circumference of the core. An example of such a machine is shown in Sato et al., U.S. Pat. No. 4,872,618.